Please add the speed ring of choice to your order. All speed rings are free of charge & will be refunded when we process your order. Please note that the Interfit Speed Ring Profoto ASA1013 is not included in this offer. Rectangular Softboxes are widely used in Fashion & Product Photography as the Speed ring means that you can rotate the box to adjust the shape of light. Some Rectangular Softboxes are used in the Interfit Stellar Halogen range of kits. Maximum Light loss=1 stop with both baffles inserted. except RSBR8511 or above which are 1.2 stops. To fit a softbox to a head you will need to know the fitting type. If it is an interfit head it is likely to be the ASA1000 ring (S Type Fitting). Supplied with: Rods. Basic Ring. Carry Bag. Dimensions: 140x 100 cm. (39 x 55").